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Non-Destructive Testing
Of Test Mock-Ups UsingInfra-Red Thermography
Santosh Pandya, Shwetang Pandyaand Dr.J.Govindarajan
Infra-Red Thermography Division
Institute for Plasma Research
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Why NDT?
Plasma Facing Components (PFCs) are the components inside thetokamak to come in contact with the hot plasma and hence are subjectedto high heat flux (HHF) of the order of few tens of M W/ m2 andbombardment of energetic particle flux (EPF) from the high temperaturefusion plasma.
The exposure to the HHF and EPF may damage the structural integrityof PFCs and shorten their service life significantly, if the bonding betweenplasma facing materials (PFMs) to heat sink is not satisfactory.
Suitable non-destructive testing (NDT) technique is thus essential toevaluate the brazing quality between the PFM and the heat sink.
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NDT of Brazed Macro-Brush using Different IR-Thermography methods
Schematic Diagram PFC with Graphite Tiles1
PFC with Tungsten Tiles1
1. Sample developed by National Aerospace Laboratories (NAL, Bangalore, INDIA) under MOU with Institute for Plasma Research (IPR, Gandhinagar, INDIA)
2. IR-Thermography Division, Institute for Plasma Research (IPR, Gandhinagar, INDIA).3. NDE Department, Indian Institute Technology-Madras (IIT-M, Chennai, INDIA).4. Quality Assurance Division, Indira Gandhi Centre for Atomic Research(IGCAR, Kalpakkam, INDIA)
Following are the active IR-NDT techniques used to examine test mock-ups
1. Transient NDT by passing Hot & Cold water through the sample 22. Heat stimulation using Induction Heating 3
3. Pulse IR-NDT 4
4. Lock-in IR-NDT 4
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Principle of Operation Lock in Thermography
N
measures surfacetemperature
s/2mconstantdiffusion
J/kgK capacityheatspecific
3kg/mdensity
W/mK tyconductivithermal
p
p
c
c
VP
!E
V
P
a periodic heat flux is incident onthe surface of interest
the surface temperature ismeasured and local variations in
the phase and/or amplitude arerequired
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Pulse thermography
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Results from different methods for a Graphite tiles sample
Heat stimulation using Induction Heating Transient NDT by passing Hot &Cold water through the sample
Lock-in IR-NDT Pulse IR-NDT
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10400
10600
10800
11000
11200
11400
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0 500 1000 1500 2000
Time (Seconds)
I R C a m e r a
S i g n a
l - D
i g i t a
l L e v e
lSeries1
Series2
Series3
Series4
Series5
Series6
Series7
Series8
Series9
Series10
Series11
Series12
Series13
Series14
Series15 -40
-30
-20
-10
0
10
20
30
40
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Tile Number
D e
l t a - P
h a s e
( D e g r e e
)
0.004 Hz0.005 Hz0.006 Hz0.007 Hz0.008 Hz0.009 Hz0.01 Hz0.02 Hz0.03 Hz0.04 Hz0.05 Hz0.06 Hz0.07 Hz0.08 Hz0.09 Hz0.1 Hz0.2 Hz0.3 Hz0.4 Hz0.5 Hz
20
25
30
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40
45
50
15 16 17 18 19 20
Time (Sec)
T e m p e r a
t u r e
( C )
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
De f ect identi f ication in di ff erent methods
Transient NDT by
passing Hot & Cold water through thesample
Pulse IR-NDT Lock-in IR-NDT
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Results from different methods for Tungsten Macro-Brush Test Mock-Ups
Transient NDT by passing Hot &Cold water through the sample
Pulse IR-NDT
Lock-in IR-NDT
TEBT
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9900
10000
10100
10200
10300
10400
10500
0 500 1000 1500 2000
T i e
Sec
s
I R C a
e r a
S i
a l
D i
i a
l e e
lSe
ie
1
Se
ie
2
Se
ie
3
Se
ie
4
Se
ie
5
Se
ie
6
Se
ie
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Se
ie
8
Se
ie
9
Se
ie
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Se
ie
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Se
ie
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Se
ie
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Se
ie
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Se
ie
15
40
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50
16
00 16
50 17
00 17
50 18
00 18
50 19
00
T i e Sec
T e
e r a
!
"
r e#
$
C%
1
2
3
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5
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8
9
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15
Pulse IR-NDT
Transient NDT by
passing Hot & Cold water through thesample
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NDT Results of Graphite Test Mock-Up using TBET Induction Heating
A tubular coil was designed to pass
through the inner passage / hole of theDIVERTORsample.The sample was heated for 5 sec andcooled at constant temperature undernatural convection.The temperature data was analyzedunder infra-red camera and recorded
Frequency used 3000 HzCurrent : 2.5-3 AmpsVoltage :40 VHeating time 5 sec
Tile with good bond Cu Tube
Tile with weak bond
Tile with good bond
Tile with weak bond
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Time History Chart
Good Tile
Defective tile
Time History Thermal Images
NDT Results of Tungsten Test Mock-Up using Induction Heating
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Conclusions
1. NDT carried out using different IR-Thermography
techniques are compared on macro-brush test mock-ups with graphite and tungsten tiles as plasma facingmaterials;
2. Among four techniques studied, Transient IR-Thermography by Hot & Cold Stimulation is foundsuitable for both Graphite and Tungsten mock-ups;
3. Results of NDT using various techniques shows goodconsistency for Graphite mock-ups.
4. More work is needed for NDT of Tungsten mock-ups.